and then… leading on from partial jump squats – surely single leg partial jump squats would then be even more specific? i think a lot of double leg stuff doesn’t necessarily transfer over to jumping performance because the load is reduced and the impact is unrealistic. an example of this would be depth jumping… i’ve seen a few guys who look great when doing two footed rebound jumps off a box but then when they try to land a hop (single leg) they just crumble and so don’t go anywhere. i reckon to achieve the ultimate specificity (for jumpers in particular), everything should be single leg, both in terms of weights and plyos. the only time i think double leg stuff is required is for younger athletes as an introduction to plyos and weights as going straight into single leg stuff would be pretty hardcore
And this is why weights arent meant to be specific, but to just gain the needed strength base. Which is so easy to do, only take 2 hours week, no assistants, no chains etc. Just to gain a little stength, THEN transfer it to the real specific stuff. Single leg squatting is somewhat of a skill and you would never do half the weight of your normal squat, and will not have the same strength gains.
Its the same reason people do planks, leg raises etc, its not specific but will help.
Isnt this what the Jamaicans are doing? Everything is general in the gym while everyone else is overcomplicating everything.